1. Field of the Invention
The present invention relates generally to a gas turbine engine, and more specifically to a variable inlet guide vane and an actuator for the variable inlet guide vane.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
A gas turbine engine includes a compressor with multiple rows of rotor blades spaced between multiple rows of stator vanes to gradually compress air for delivery to a combustor. Many gas turbine engines include a first stage of inlet guide vanes that are variable in order to change the angle of each guide vane.
In many engines with variable inlet guide vanes, each vane is pivotably connected to an actuator in which a radial extending pin passes through a hole formed within the casing that is attached to an actuator or to a linkage that is attached to an actuator. Each guide vane includes a pin that extends through a separate hole formed in the casing so that each guide vane can be moved together. Because each guide vane requires a hole in the casing, leakage of the air flow passing through the guide vanes is high.
In the variable inlet guide vanes of the prior art in which each guide vane includes a linkage to connect it to the driving motor, the linkage is complex with several linkages that create a complex assembly, and that will involve large tolerances especially when wear occurs between the links.
Another issue with the prior art variable inlet guide vanes is that the actuator used to drive the guide vanes is a rather large piston cylinder that is both heavy and takes up a lot of space. In an aero engine of the type used to power an aircraft, both weight and size are important matters related to the engine efficiency. Space is limited for the engine and its components. The prior art actuators are large linear piston actuators that drive the linkage connecting the guide vanes.